1. Field of the Invention
The present invention relates to a conductivity testing method for a sub-harness to be arranged on a vehicle such as motor vehicle and to a sub-harness manufacturing apparatus.
2. Description of the Related Art
A pressure welding apparatus, which has a pair of frames with a pair of pressure welding units and a pair of connector tables so that many kinds of sub-harnesses composing a wiring harness can be effectively manufactured, is suggested in Japanese Patent Application Laid-open No. 10-154568
The pressure welding apparatus enables a wire to be pressure-welded to a connector on one connector table, while supplying another connector on the other connector table. And, a sub-harness can be collected from the. other connector table.
With respect to the above prior art, however, the sub-harness having been collected from the connector table is to be set on a conductivity test tool so that the conductivity can be tested through terminals connected on the both ends. In case that conductivity defectiveness is found many man-hours are required for its repair, thereby increasing the cost.
In view of the foregoing, an object of the present invention is to provide a conductivity testing method for a sub-harness and a sub-harness manufacturing apparatus, wherein a sub-harness can be efficiency manufactured and tested.
In order to achieve the above object, as a first aspect of the present invention, a conductivity testing method for a sub-harness in a sub-harness manufacturing process using a sub-harness manufacturing apparatus, the sub-harness manufacturing apparatus comprising: a pair of connecting units each having a wire connecting portion, made of metal, vertically movable so as to connect one end of one of wires composing a sub-harness to one of terminals having a sheathing clamping portion and being arranged in a wire feeding direction; and a pair of transferring means to transfer the terminals in a direction perpendicular to the wire feeding direction so as to position each one of the terminals under each wire connecting portions, wherein a clamping punch portion to clamp the sheathing clamping portion is provided on the wire connecting portion of each of the pair of connecting units, comprises the steps, in a connection process of connecting both ends of the one of the wires to the respective terminals, of: keeping one clamping punch portion having clamped the sheathing clamping portion onto one end of the one of the wires in contact with the sheathing clamping portion; keeping the other clamping punch portion having clamped the sheathing clamping portion onto the other end of the one of the wires in contact with the sheathing clamping portion; and testing conductivity between one and the other clamping punch portions so as to judge the one of the wires having the terminals on the respective ends being good or bad.
As a second aspect of the present invention, a sub-harness manufacturing apparatus comprises: a pair of connecting units each having a wire connecting portion, made of metal, vertically movable so as to connect one end of one of wires composing a sub-harness to one of terminals having a sheathing clamping portion and being arranged in a wire feeding direction; and a pair of transferring means to transfer the terminals in a direction perpendicular to the wire feeding direction so as to position each one of the terminals under each wire connecting portions, wherein a clamping punch portion to clamp the sheathing clamping portion is provided on the wire connecting portion of each of the pair of connecting units and a conductivity testing means to judge the one, having terminals on the respective ends thereof, of the wires being good or bad is arranged between the clamping punch portions of the pair of connecting units.
As a third aspect of the present invention, in the structure with the above second aspect, each of the pair of connecting units is provided with a holding means to keep the clamping punch portion in contact with the sheathing clamping portion.
As a fourth aspect of the present invention, in the structure with either one of the above first and second aspects, the sub-harness manufacturing apparatus further comprises: a controlling means to synchronize a timing to clamp the sheathing clamping portion onto the one end of the one of the wires with a timing to clamp the sheathing clamping portion onto the other end of the one of the wires.
As a fifth aspect of the present invention, in the structure with any one of the above second to fourth aspects, the terminals transferred by at least one of the pair of transferring means are of pressure welding terminals each having a pair of pressure welding edges and being accommodated in respective grooves provided in parallel on an insulative body, and an wire pressure welding blade to pressure-weld one or the other end of the one of the wires is formed on the corresponding wire connecting portion.
According to the present invention with the above first aspect, each wire having the terminals and thereby forming the sub-harness is tested in a manufacturing process of the sub-harness. That is, the terminal is electrically connected to the wire at each connecting unit, the wire connecting portion is kept in contact with the terminal in a state of the wire connecting portion having clamped the sheathing clamping portion, and the conductivity between the clamping punch portions of the respective wire connecting portions is checked. That is, a circuit (i.e. one clamping punch portionxe2x80x94one sheathing clamping portionxe2x80x94wirexe2x80x94the other sheathing clamping portionxe2x80x94the other clamping punch portion) for the conductivity test is formed, whereby each wire having the terminals and composing the sub-harness is tested.
According to the present invention with the above second aspect, since the conductivity testing means is arranged between the clamping punch portions of the respective wire connecting portions of the pair of connecting units, each wire having the terminals and composing the sub-harness can be tested. And, the circuit for the conductivity test is formed by making the clamping punch portions contact with the respective sheathing clamping portions of the wire. By this, each wire having the terminals and composing the sub-harness can be tested by means of the conductivity testing means.
According to the present invention with the above third aspect, since the wire connecting portion can hold the terminal in a state of the sheathing clamping portion being clamped, while keeping in contact with the sheathing clamping portion, even if there is a timing gap of the operation between the wire connecting portions of the pair of connecting units, either one of the wire connecting portions can wait for the other, while keeping in contact with the sheathing clamping portion of the terminal.
According to the present invention with the above fourth aspect, the sheathing clamping portions to be connected to the respective ends of the wire can be clamped simultaneously. Therefore, the test can be carried out simultaneously with the clamping of the sheathing clamping portions.
According to the present invention with the above fifth aspect, at least one connecting unit of the pair of connecting units can be used as a pressure welding unit.
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.